Question

All are true about skin except:

• A. Both dermis and epidermis are derived from ectoderm
• B. Skin accounts for a total of 15% of body weight
• C. Most of the cells in skin are keratinocytes derived from ectoderm
• D. Dermis is made up of type 1 and type 3 collagen in a 3:2 ratio

Hint:

Epidermis is ectoderm but dermis is mesoderm.

Answer 1

The Correct Option is A

Step 1: This is a negative-stem question, so the false statement is the answer.
Step 2: Skin has two embryological origins. The epidermis (and its appendages) is derived from ectoderm, while the dermis is derived from mesoderm. The statement that both dermis and epidermis come from ectoderm is therefore FALSE.
Step 3: The other options are correct: skin is roughly 15% of body weight, keratinocytes are the predominant epidermal cell and are ectodermal in origin, and the dermis is rich in type 1 and type 3 collagen.
Step 4: Hence option 1 is the exception and is the correct choice.